This research project will investigate the mucosa adherence mechanism(s) employed by Haemophilus influenzae type b (Hib) to colonize the human naso/oropharynx. A specific in vitro assay system, employing either light microscopy or radioisotope techniques, will be developed for quantitation of Hib adherence to human oropharyngeal epithelial cells. Both tissue culture cell lines and tracheal organ culture systems will be investigated for their suitability as model systems for studying Hib adherence. Studies of Hib adherence to human oropharyngeal cells will include examination of the relationship of this adherence process to both Hib cell physiology and virulence of this pathogen. Biochemical and structural characteristics of the adherence factor(s) on the cell surface of Hib will be elucidated by enzymatic methods. Final immunologic identification of the Hib cell surface component(s) involved in the adherence process will involve the use of pure monoclonal antibodies, produced by lymphocyte hybridomas. Lymphocyte hybridomas synthesizing monoclonal antibodies directed against the capsule, lipopolysaccharide, and outer membrane/cell surface proteins of Hib will be constructed by fusing mouse myeloma cells to spleen cells from Hib-immunized mice.